bug#32903: [PATCH] Display uncompressed size when testing

[Stephen Kitt]

Hi Sergey,

On Sun, 4 Nov 2018 14:49:50 +0200, Sergey Ponomarev <address@hidden> wrote:
> > Alongside the OK message, print the real size in bytes; this provides  
> a way to view the stored file's size when it's larger than 4GiB.
> 
> You can get a real size by `gzip --list` command. Why to show the size in
> `gzip --test` output? Almost all other compressors (lzop, xz, bzip2, etc0
> just shows the same message:
> filename: OK

"gzip --list" only reports sizes correctly up to 4GiB; see the BUGS section in
the manpage:

       The  gzip  format represents the input size modulo 2^32, so the --list
       option reports incorrect uncompressed sizes and compression ratios
       for uncompressed files 4 GB and larger.

> Even more, archive manages and other tools may try to parse the test
> command output and the change may have some impact.

True, I haven’t checked the impact much — although I’ve been running gzip
with this patch for a while without adverse effects (but that’s anecdotal).

> > this provides a way to view the stored file's size when it's larger than  
> 4GiB.
> I didn't get it. Can you please elaborate on this: `gzip --list` can't show
> uncompressed size more than 4GiB?

See above.

Regards,

Stephen

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